Bird gets worm, makes history

A pied-billed grebe, a bird that is built for swimming, not walking, scoots up a mud bank to catch an earthworm, a hunting behavior never before described in the scientific literature. Graphic by Julie McMahon

CHAMPAIGN, Ill. — It’s a warm April evening, and the air and earth are still heavy with moisture from recent rains. I’m perched on a plastic patio chair on my balcony when something catches my eye. I grab my binoculars and make out the details of a small bird paddling around in a new retention pond. It’s a pied-billed grebe, and it’s acting oddly.

Grebes are diving specialists and almost never venture onto land. In fact, their feet are designed to propel them underwater in pursuit of aquatic prey. Their legs are positioned so far back on their bodies that standing or walking on land is extremely difficult and very rare.

Nonetheless, this bird is cruising the pond’s edge, inspecting the gently sloping shore with great interest. I watch, perplexed. Why is it staying so close to shore? What transfixes it so?

After a few minutes of scanning, the grebe bursts out of the water onto the shore, propelling itself with its feet and scooting on its belly. About two meters from the water’s edge, it grabs something from the bare soil, turning and scooting back down the bank and into the water. Its hasty foray onto land lasts about five seconds.

In its bill is a large, writhing earthworm, about 6 inches in length. The grebe dunks the worm a few times and – I’m assuming – gulps it down.

I know what I’ve just witnessed is unusual. No one has ever recorded a grebe of any species foraging on land. I’m guessing the bird had no luck finding food in the recently constructed pond, and so turned its sights toward the bounty on land. Poor mobility on land is no obstacle when a tasty treat presents itself nearby.

And, just like that, a casual evening on my balcony yields a new natural history observation. It will soon be part of the peer-reviewed literature in the the Wilson Journal of Ornithology.

Subscribe to Behind the Scenes for short blog posts, photos and videos from Illinois faculty, researchers, students and staff about their work and lives. Send an email with “SUBSCRIBE BTS” in the subject line.